Efficacy of rotten and fresh fruit extracts as the photosensitive dye for dye-sensitized solar cells
(1) Sir Winston Churchill Secondary School, St. Catharines, ON, Canada, (2) School of Interdisciplinary Sciences, McMaster University, Hamilton, ON, Canada, (3) Department of Plant Agriculture, University of Guelph, Vineland Station, ON, Canada
Global demand for energy is increasing exponentially, developing the need for renewable energy sources such as solar cells. Dye-sensitized solar cells (DSSC) use dye as the photoactive material, which capture the incoming photon of light and use the energy to excite electrons. These excited electrons then travel to a titanium dioxide (TiO2) layer, while the electrolyte in the cell closes the circuit by accepting the electrons and recycling them to the dye. Research in DSSCs has centered around improving the efficacy of photosensitive dyes. A fruit's color is defined by a unique set of molecules, known as a pigment profile, which changes as a fruit progresses from ripe to rotten. This project investigates the use of fresh and rotten fruit extracts as the photoactive dye in a DSSC. Dyes were extracted from cherries, plums, nectarines, peaches, kiwis, avocados, blueberries, and blackberries, both fresh and rotten. TiO2 coated electrodes were soaked overnight in the dyes and assembled into a DSSC using a graphite-coated counter electrode and an iodide-triiodide (3I-/I3-) electrolyte solution. The dye efficacy was determined by measuring the electric potential (voltage) with a multimeter. In fresh fruits, blackberries and blueberries produced the greatest potential. In most colors, the fresh dyes produced a greater potential than the rotten dyes. However, in kiwi, the rotten dye produced a greater potential than the fresh dye. In fruit crops, wastage levels are high due to quick rotting and market standards — the use of fruit-based dyes in DSSCs can convert this wastage to useful energy.